This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project is part of a contract project with Merck Frosst Centre for Respiratory Imaging, Robarts Research Institute, Ontario, Canada The primary aim is to clearly demonstrate the ability of 3He imaging to differentiate the airway hyper-responsiveness phenotype in several mouse models of asthma as specified by Merck. Various image analysis and quantification paradigms will be tested. An initial aim is to integrate Merck's specialized 3He ventilator with the imaging. The project is thus broken down into three stages and associated milestones. --Stage I is to test the performance of the Merck ventilator against the Duke ventilator for hyperpolarized 3He delivery and imaging. -- Simultaneously, the Merck asthma model will be implemented and evaluated at Duke by Dr. Mike Foster. -- Once a suitable ventilator is chosen, Stage II will employ 3He imaging to test differences in AHR between an OVA/PBS mouse and an OVA/OVA mouse.